Blue Whale
Balaenoptera musculus
The largest animal that has ever existed. Ever. Including dinosaurs.
Nothing in the entire fossil record beats a blue whale for size. It is longer than a basketball court, heavier than 30 elephants, and it built all of that out of shrimp the size of your thumb.
On the conservation status
Whaling killed roughly 99% of Antarctic blue whales in the twentieth century. They have been protected since 1966 and are slowly coming back.
- Length
- 24–30 m (79–98 ft)
- Weight
- Up to 180,000 kg (200 tons)
- Lifespan
- 80–90 years
- Diet
- Krill, and basically nothing else
- Heart
- About 180 kg (400 lb)
- Calf at birth
- 7.5 m and 2,700 kg
The good stuff.
Four tons of krill a day
That's around 40 million individual krill, every single day, during feeding season. They lunge with their mouth open so wide the throat balloons out like a parachute.
The heart is the size of a golf cart
It weighs about 400 pounds and beats as slowly as twice a minute on a deep dive. The main artery is wide enough for a child to crawl through.
Their voice crosses oceans
Blue whale calls reach 188 decibels — louder than a jet engine — at frequencies so low we can barely hear them. Those calls can travel hundreds of kilometres through deep water.
Babies gain 90 kg a day
A blue whale calf drinks around 200 litres of milk daily. The milk is roughly 40% fat, closer to toothpaste than to anything you'd pour on cereal.
The tongue weighs as much as an elephant
And their mouth can hold up to 90 tonnes of water and food at once — though the throat itself is only about the width of a dinner plate.
They're blue-ish, actually
Up close a blue whale is mottled blue-grey. Under water, the light makes it glow properly blue. In cold seas a film of yellowish algae can even tint their bellies, which earned them the old nickname sulphur-bottom.
Wait, really?
- ✦
A blue whale's blow shoots 9 metres into the air — you can spot it from kilometres away.
- ✦
Their earwax builds up in layers like tree rings, and scientists read it to work out a whale's age and stress.
- ✦
Roughly 10,000–25,000 blue whales are left, down from perhaps 350,000 before whaling.
What it sounds like
Deep, slow moans and pulses below 20 Hz — so low that you feel them in your chest more than you hear them.
Where you might see one
Monterey Bay and the Channel Islands in California, the Sea of Cortez, Sri Lanka's south coast, and Iceland in summer.
The trouble
- Ship strikes
- Entanglement in fishing gear
- Krill loss as the ocean warms
- Ocean noise masking their calls
One real thing
Back the ship slow-down zones in whale feeding grounds. Slower ships kill far fewer whales.
More ways to help